Juan, I don't want to distract the main topic, but I don't think you need what you are asking for for the Basic LTI Provider. You simply need to suppress the CFG option on the launch url and then later in the code for launch, simply check the cfg option and then do an open in new window via JavaScript instead of redirect and I then the rest of the pages function perfectly with the header set per the wishes of the admin. If the admin wants to let it work in the iframe, simply change the cfg globally and your code will then let the tools/courses nestle snugly in the iframe.
Again, I don't intend to distract from your high level conersation about more places to add plugins.